The nitrone derivatives such as phenyl-t-butylnitrone (PBN) have been used as spin-traps to detect free radicals by electron spin resonance (ESR). J. Org. Chem., 57, 2624(1992) describes the syntheses of various mono-substituted PBN derivatives and their effects as spin traps.
It has been reported that the nitrone derivatives such as PBN would be useful as medicaments for treating the diseases caused by active oxygen damages (e.g. ischemia, infection, inflammation, radiation damages, damages of central or peripheral nervous systems or peripheral organs caused by drug abuse, etc.) by acting as antioxidants (WO 91/5552; WO 92/22290; WO 95/17876; J. Biol. Chem., 271, 3097(1996)). However, these documents do not disclose that these compounds are effective for treating retinal degenerative disorders. It is also reported that free radicals such as active oxygen have some relation with retinal damages caused by light (A. M. Van Der Hagen, et al., J. Am. Optom. Assoc., 64, 871(1993)).
JP 54-2324 (A) discloses the syntheses of compounds useful as insecticides using N-t-butyl-4-chlorobenzylamine, N-t-butyl-2,4-dichlorobenzylamine and the like as synthetic intermediates.